Aperture problem with Tamron SP 90mm 2.8 Di Macro lens

femto · 01-05-2022, 08:47 AM

Hurray! My new (used) macro lense arrived today. The seller told me the autofocus does not work and I got it for a really good price.
While the non-functioning autofocus does not bother me at all, there actually seems to be a second problem that I was not aware of when I bought it. The aperture simply won't open when the lens is mounted to my K-50. It is always dark in automatic mode, and when I preset the aperture using the ring, it stays at that aperture even when focusing. As a result the lense is completely unusable for me as I typically shoot between f11-f16.

Is this a known (fixable) problem or should I kindly ask my money back? I actually asked if there are more problems that I should know about and the answer was "no". I am feeling quite puzzled right now. Do I have to bend out the aperture lever maybe as it appears to be quite far towards the center? I can open the blades using my fingers after all.

I am also curious if the autofocus can be repaired DIY, but that one is not too important.

Thanks for any help or advice!

Edit: I tried the lens on my K100 Super and it behaves a bit different there. If I turn the aperture ring starting from wide open the blades will be completely open at F2.8 and gradually close until F8 when nothing is happening anymore. In "A" setting, the blades will only open up a tiny bit. The same is true when I remount the lense while having it in "A" position. It must be because of some sort of contact issue between lense and camera. But how fo fix it?

Edit: The blades are actually closing down better if I put an extension tube between camera and lens, but they still stop closing down any further at higher f-stops.

[PROBLEM SOLVED]

I opened up the back plate, bent the lever and after that both the aperture blades and the auto focus work perfectly fine. I am not sure what caused the AF to not work, but I am happy it does now. =)
It was neither caused by the limiter nor the lens or camera being in manual mode.

Last edited by femto; 01-05-2022 at 12:24 PM.

reh321 · 01-05-2022, 09:30 AM - **1 Like**

The body moves the aperture via a small lever on the lens mount.
If you set the lens to "A" or to a large number {like f/22}, this lever should move freely.
This is the first thing I would check - but honestly, I've never had this kind of problem.

femto · 01-05-2022, 09:46 AM

Originally posted by reh321

The body moves the aperture via a small lever on the lens mount.
If you set the lens to "A" or to a large number {like f/22}, this lever should move freely.
This is the first thing I would check - but honestly, I've never had this kind of problem.

Thanks for the reply!

It does move freely, but it won't do anything when mounted to the camera.
Is it safe to bend the lever towards the outside? There is absolutely no space between the lever and that piece of plastic that is sticking out. I added some pictures in my initial post to show what I mean.

Not a Number · 01-05-2022, 11:19 AM - **2 Likes**

It looks to me from the photo as if the lever is bent towards the shield and center of the lens. It may not be engaging the lever in the camera.

Compare it to other lenses that you have that work.

femto · 01-05-2022, 12:04 PM - **3 Likes**

Originally posted by Not a Number

It looks to me from the photo as if the lever is bent towards the shield and center of the lens. It may not be engaging the lever in the camera.

Compare it to other lenses that you have that work.

I actually opened up the lens from the back so I could repair it. With the mount off I was able to safely bend it into another position The first try was too far, but on the second atempt it worked fine. I also bend two wires that make contact with the pcb when the lens in in A setting because one of them looked really loose. Somehow - I don't know if that was the actual reason, the AF is working again. So my repair attempt was a total success! =D

The difficult part was to refit the small metallic ball that's responsible for the click stops. I lost it multiple times. Stupid me! I really should have used some sort of tablet to prevent it from rolling off the table I was working on. At one point I was wondering if I should just keep it declicked.

Anyway, I am super happy now with a fully working lens that I got for a bargain price!

Paul the Sunman · 01-05-2022, 01:24 PM - **1 Like**

When mine arrived many years ago, new, the aperture lever was badly bent out of shape. I straightened it by hand, and it has worked perfectly ever since.

Not a Number · 01-05-2022, 04:19 PM - **2 Likes**

Sweep the area with a magnet and you might find the bearing. Or cover the end of a vacuum cleaner tube with a very fine mesh like some pantyhose stocking and vacuum around the area. That's what some machine shops do.

IF the A pin doesn't connect, AF usually won't work.

**photogem** · 01-06-2022, 01:29 AM - **1 Like**

Originally posted by femto

I actually opened up the lens from the back so I could repair it. With the mount off I was able to safely bend it into another position The first try was too far, but on the second atempt it worked fine. I also bend two wires that make contact with the pcb when the lens in in A setting because one of them looked really loose. Somehow - I don't know if that was the actual reason, the AF is working again. So my repair attempt was a total success! =D

The difficult part was to refit the small metallic ball that's responsible for the click stops. I lost it multiple times. Stupid me! I really should have used some sort of tablet to prevent it from rolling off the table I was working on. At one point I was wondering if I should just keep it declicked.

Anyway, I am super happy now with a fully working lens that I got for a bargain price!

That was good work!

Next time you have to open a lens with such a ball, magnetize one extra screwdriver and keep that ball "glued" to it.
Then place a tiny amount of grease which will hold it in position when reassembling.

I sometimes have similar problems with the tiny JIS screws, sometimes one falls onto the floor.

Because my wooden floor has tiny gabs at places I use a magnet but the idea with the vacuum cleaner and mesh or pantyhouse stocking is very good.

01-05-2022, 08:47 AM	#1
femto New Member Join Date: Oct 2021 Posts: 8	Aperture problem with Tamron SP 90mm 2.8 Di Macro lens Hurray! My new (used) macro lense arrived today. The seller told me the autofocus does not work and I got it for a really good price. While the non-functioning autofocus does not bother me at all, there actually seems to be a second problem that I was not aware of when I bought it. The aperture simply won't open when the lens is mounted to my K-50. It is always dark in automatic mode, and when I preset the aperture using the ring, it stays at that aperture even when focusing. As a result the lense is completely unusable for me as I typically shoot between f11-f16. Is this a known (fixable) problem or should I kindly ask my money back? I actually asked if there are more problems that I should know about and the answer was "no". I am feeling quite puzzled right now. Do I have to bend out the aperture lever maybe as it appears to be quite far towards the center? I can open the blades using my fingers after all. I am also curious if the autofocus can be repaired DIY, but that one is not too important. Thanks for any help or advice! Edit: I tried the lens on my K100 Super and it behaves a bit different there. If I turn the aperture ring starting from wide open the blades will be completely open at F2.8 and gradually close until F8 when nothing is happening anymore. In "A" setting, the blades will only open up a tiny bit. The same is true when I remount the lense while having it in "A" position. It must be because of some sort of contact issue between lense and camera. But how fo fix it? Edit: The blades are actually closing down better if I put an extension tube between camera and lens, but they still stop closing down any further at higher f-stops. [PROBLEM SOLVED] I opened up the back plate, bent the lever and after that both the aperture blades and the auto focus work perfectly fine. I am not sure what caused the AF to not work, but I am happy it does now. =) It was neither caused by the limiter nor the lens or camera being in manual mode. Last edited by femto; 01-05-2022 at 12:24 PM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Questions about the Tamron SP-AF Di 90mm f/2.8 1:1 Macro Lens	brainwave	Pentax SLR Lens Discussion	7	10-28-2021 01:37 AM
For Sale - Sold: Tamron 272E AF 90mm f2.8 SP Di Macro Lens 90mm Mint Condition	rosettaquarrier	Sold Items	3	06-26-2020 01:59 PM
For Sale - Sold: Tamron SP AF 90mm f2.8 Di MACRO - slight problem, please read	Quazimoto	Sold Items	3	09-24-2013 03:23 AM
For Sale - Sold: Pentax K-r, Tamron SP 17-50/2.8, Tamron SP 90mm Macro, Metz 48 AF-1, and more	stillshunter	Sold Items	9	10-03-2011 01:42 AM
For Sale - Sold: Tamron SP 90mm/2.8 macro (AF), Tamron SP 90mm/2.5 macro (MF)	chemxaj	Sold Items	11	06-19-2008 08:36 PM

01-05-2022, 09:46 AM	#3
femto New Member Join Date: Oct 2021 Posts: 8 Original Poster	Originally posted by reh321 The body moves the aperture via a small lever on the lens mount. If you set the lens to "A" or to a large number {like f/22}, this lever should move freely. This is the first thing I would check - but honestly, I've never had this kind of problem. Thanks for the reply! It does move freely, but it won't do anything when mounted to the camera. Is it safe to bend the lever towards the outside? There is absolutely no space between the lever and that piece of plastic that is sticking out. I added some pictures in my initial post to show what I mean.

01-05-2022, 11:19 AM - 2 Likes	#4
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	It looks to me from the photo as if the lever is bent towards the shield and center of the lens. It may not be engaging the lever in the camera. Compare it to other lenses that you have that work.

01-05-2022, 12:04 PM - 3 Likes	#5
femto New Member Join Date: Oct 2021 Posts: 8 Original Poster	Originally posted by Not a Number It looks to me from the photo as if the lever is bent towards the shield and center of the lens. It may not be engaging the lever in the camera. Compare it to other lenses that you have that work. I actually opened up the lens from the back so I could repair it. With the mount off I was able to safely bend it into another position The first try was too far, but on the second atempt it worked fine. I also bend two wires that make contact with the pcb when the lens in in A setting because one of them looked really loose. Somehow - I don't know if that was the actual reason, the AF is working again. So my repair attempt was a total success! =D The difficult part was to refit the small metallic ball that's responsible for the click stops. I lost it multiple times. Stupid me! I really should have used some sort of tablet to prevent it from rolling off the table I was working on. At one point I was wondering if I should just keep it declicked. Anyway, I am super happy now with a fully working lens that I got for a bargain price!

01-05-2022, 01:24 PM - 1 Like	#6
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,843	When mine arrived many years ago, new, the aperture lever was badly bent out of shape. I straightened it by hand, and it has worked perfectly ever since.

01-05-2022, 04:19 PM - 2 Likes	#7
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Sweep the area with a magnet and you might find the bearing. Or cover the end of a vacuum cleaner tube with a very fine mesh like some pantyhose stocking and vacuum around the area. That's what some machine shops do. IF the A pin doesn't connect, AF usually won't work.

01-06-2022, 01:29 AM - 1 Like	#8
photogem Site Supporter Join Date: Apr 2015 Posts: 3,520	Originally posted by femto I actually opened up the lens from the back so I could repair it. With the mount off I was able to safely bend it into another position The first try was too far, but on the second atempt it worked fine. I also bend two wires that make contact with the pcb when the lens in in A setting because one of them looked really loose. Somehow - I don't know if that was the actual reason, the AF is working again. So my repair attempt was a total success! =D The difficult part was to refit the small metallic ball that's responsible for the click stops. I lost it multiple times. Stupid me! I really should have used some sort of tablet to prevent it from rolling off the table I was working on. At one point I was wondering if I should just keep it declicked. Anyway, I am super happy now with a fully working lens that I got for a bargain price! That was good work! Next time you have to open a lens with such a ball, magnetize one extra screwdriver and keep that ball "glued" to it. Then place a tiny amount of grease which will hold it in position when reassembling. I sometimes have similar problems with the tiny JIS screws, sometimes one falls onto the floor. Because my wooden floor has tiny gabs at places I use a magnet but the idea with the vacuum cleaner and mesh or pantyhouse stocking is very good.